The implantation of a medical device, such as a pacemaker and/or defibrillator, for the purposes of stimulating and/or controlling the heart muscle activity of a patient, involves positioning one or more electrical leads inside the body of the patient. Specifically, these electrical leads extend through the body between a subcutaneously positioned electronic device and the heart.
Although each electrical lead is essentially unitary along its length, different segments of a lead are subjected to different functional environments. For one, the distal segment of the electrical lead, which is placed in direct contact with the heart muscle, must be held relatively stationary. On the other hand, the proximal segment of the electrical lead, which is electrically connected with the electronic device (e.g. a pacemaker or defibrillator pulse generator), must be flexible and responsive to the physical activity of the patient. To effectively establish these different environments (i.e. stability and flexibility), the proximal and distal segments of the electrical lead are separated by a so-called “tie down” which effectively stabilizes only the distal segment of the electrical lead.
For a proper operation of the medical device, it is essential that the electrical integrity of each implanted lead(s) be maintained, and uncompromised, throughout its entire length. As a practical matter, due to the activity that is typically experienced in the proximal segment of the electrical lead, this segment is more susceptible to damage. This proximal segment, however, is more easily accessible and, indeed, can be accessed without adversely disturbing the stability of the distal segment. Nevertheless, both segments (proximal and distal) should be periodically checked for their electrical integrity. When and how this is to be done will be best left to the judgment of the attending physician.
With the above in mind, it is an object of the present invention to provide a system and method for testing the electrical integrity of a proximal segment of an electrical lead that is used with an implanted medical device. It is another object of the present invention to provide a device for inspecting a proximal segment of a pacemaker or defibrillator lead while a distal segment of the lead remains operationally positioned in a patient's body. Yet another object of the present invention is to provide an extracorporeal unit for inspecting the insulation of an electrical wire of an implanted medical device and corresponding methods of use which are easy to use, relatively simple to implement, and comparatively cost effective.